1. Field of the Invention
The present invention relates, in general, to an optical modulator module package and, more particularly, to an optical modulator module package using a flip-chip mounting technology, in which easy electrical signal transmission between an optical modulator device and driver integrated circuits and hermetic mounting to desirably maintain characteristics of the optical modulator device are simultaneously achieved using the flip-chip mounting technology.
2. Description of the Related Art
Recently, many applications and products have been developed using a micro electromechanical system (MEMS) technology, and are used in daily life.
Most MEMS products comprise movable components, and are affected by surface energy rather than energy caused by mass, due to a micrometer(μm)-sized fine structure.
Accordingly, in order to assure stable and reliable performance of the products, movement of movable structures must be shielded from mechanical and chemical external factors and be separated from factors capable of affecting surface energy. To satisfy the above-mentioned demand, a study has been made of hermetic packaging for a MEMS device.
Currently, in the case of a reflective diffraction type of optical modulator among MEMS devices, in comparison with integration of the optical modulator and driver integrated circuits on the same device, it is believed more preferable to form the driver integrated circuits on another device so as to form a hybrid-type structure by modularization, in terms of yield and cost. Thus, production of the hybrid type is common.
Since the optical modulator device uses light, unlike a conventional device, conventional modularized structures and modularization processes cannot be used and should be mostly modified. Particularly, an optical modulator device is susceptible to moisture due to movement of active devices, thus hermetic mounting is necessary. Additionally, it is preferable to integrate an integrated device for driving the optical modulator device on the same device or to mount the integrated device in the same housing so as to produce a compact module structure and to make signal connection to the exterior easy.
Hermetic packaging of the conventional optical modulator device is generally conducted through a soldering method using attachment of a metal by fusion.
FIG. 1 is a sectional view of a conventional optical modulator device package, which is disclosed in U.S. Pat. No. 6,303,986.
As shown in FIG. 1, in the optical modulator device package disclosed in U.S. Pat. No. 6,303,986, solderable materials 120, 124 which are formed on a cover 122 and a passivation layer 114 are packaged using solders 126. This soldering method is capable of assuring excellent hermetic property and reliability of MEMS products.
However, in views of price competitiveness, yield, processability, and miniaturization, it is necessary to reduce the sizes of an optical modulator device and a module, thus there is growing a need to modify the structure and method of electrical signal connection between the optical modulator device and external driver integrated circuits, and a sealing structure.